Earth:Blackstone Formation, Australia

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Blackstone Formation
Stratigraphic range: Carnian-Norian
~235–206 Ma
TypeGeological formation
Unit ofIpswich Coal Measures
Sub-unitsDenmark Hill Insect Bed, Striped Bacon Seam Member
UnderliesUnconformity with Raceview Formation and Aberdare Conglomerate
OverliesTivoli Formation
Thickness200–240 m (660–790 ft)
Lithology
PrimaryShale
OtherSiltstone, coal, tuff
Location
Coordinates [ ⚑ ] : 27°36′S 152°48′E / 27.6°S 152.8°E / -27.6; 152.8
Paleocoordinates [ ⚑ ] 58°36′S 101°00′E / 58.6°S 101.0°E / -58.6; 101.0
RegionIpswich
Country Australia
Type section
Named forBlackstone, Queensland
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The Blackstone Formation is a geologic formation of the Ipswich Coal Measures Group in southeastern Queensland, Australia, dating to the Carnian to Norian stages of the Late Triassic. The shales, siltstones, coal and tuffs were deposited in a lacustrine environment. The Blackstone Formation contains the Denmark Hill Insect Bed.

Fossil content

Vertebrates

Lungfish

Dipnoans of the Blackstone Formation
Genus Species State Abundance Notes Images
Ceratodus C. robustus
Ceratodus.jpg

Invertebrates

Insects of the Blackstone Formation
Genus Species Location Stratigraphic position Material Notes Images
Mesochorista[1] M. proavita Ipswich A Permochoionid
Mesochorista proavita.jpg
Mesodiphthera M. grandis Tettigarctid cicada
Tardilly T. dunstani
T. prosboloides
Phanerogramma P. australis Dermapterid earwig
Dinmopsylla D. semota Dinmore clay pit Archipsyllid Permopsocid
Mesopsyche M. triareolata Dinmore clay pit Mesopsychid mecopteran

Ichnofossils

In 1964, dinosaur footprints were discovered from the Rhondda colliery (underground coal mine) 230 metres below ground along the sandstone ceiling of the Striped Bacon coal seam.[2] These were initially described as Eubrontes, a type of predatory dinosaur (theropod) footprint. Later, these footprints were considered as evidence for the world's largest Triassic theropod, with legs towering over 2 metres tall.[3] A 3D evaluation of the fossil indicated the footprint length was much smaller than previously reported (34 cm rather than 46 cm long) and its shape was characteristic of the trace fossil genus (ichnogenus) Evazoum.[4] The existing hypothesis is that Evazoum were made by prosauropods, ancestral forms of long-necked sauropod dinosaurs. The bipedal dinosaur track-maker may have resembled the dinosaur Plateosaurus, and this fossil is the only evidence of this group of dinosaurs in Australia. The next evidence for sauropodomorphs in Australia comes over 50 million years later in the Jurassic.

See also

References

Bibliography

  • Staines, H. R. E., and J. T. Woods. 1964. Recent discovery of Triassic dinosaur footprints in Queensland. The Australian Journal of Science 27. 1–55.